1. Field of the Invention
The present invention relates to a device for sampling solids from a sealed enclosure such as, for example, a silo, a hopper, a reactor, a regenerator or an adsorber, and to a method using the same. The invention more particularly relates to a sampling device allowing gravity sampling of the solid samples in form of granules, extrudates, balls, like those used for a catalyst or an adsorbent for example.
2. Description of the Prior Art
When divided solids are fed into enclosures operating under high pressure and/or temperature conditions or when they are arranged in enclosures where they are stored or transported by gravity, it is often necessary to take a sample of the solid.
The main purpose of this sampling is to check the mechanical or physico-chemical properties of the solid and thus to detect possible impurities settled at the surface thereof or to monitor the evolution of the quality of the stored solid stored or the solid in motion.
Sampling notably allows understanding the reasons for a possible malfunction, to check the solid storage behavior over time or to predict the maximum operation time for the solid and thus to fix or to anticipate possible problems.
In the case of refinery plants using divided solids, it may also facilitate monitoring of the unit comprising the content of the enclosure, a catalytic reactor for example, and thus enable the operation thereof to be optimized.
U.S. Pat. No. 4,009,618 notably discloses a sampling device allowing taking of samples of solid materials from a sealed enclosure such as a reactor, for example, providing catalytic cracking of hydrocarbons in the presence of a catalyst. These samplings are performed using a sampling head fed into the enclosure and carried by the body of the device. This head comprises a receptacle provided with a recess in the upper and lower part, and two slotted rotary discs driven in rotation by a shaft controlled by any known means. During a first rotation of these discs, a solid sample enters the receptacle through the upper recess controlled by one of the discs while the other disc seals the recess in the lower part. After another rotation of these discs, the upper recess is sealed by one of the discs while the other disc clears the recess in the lower part so that the solid sample is sent to a collection means.
However, the drawback of such devices is that they may jam during solid sampling operations.
Indeed, jamming can be due to the solid that may be partly crushed and/or stuck in certain moving parts, to scratches present on the constituent parts of the sampling device, or to expansions occurring on mobile parts with narrow tolerance ranges.
Depending on the more or less frequent use and on the operating conditions, the device can have operability problems as a result of the jamming of the various mobile parts, or it can even be out of order when the mobile parts are stuck.
In order to overcome this drawback, pneumatic devices or devices using gas flows for conveying the solid are provided, as described, for example, in U.S. Pat. Nos. 3,653,265 or 3,786,682. These devices allow mechanical problems to be avoided, but they involve the drawback of conveying small amounts of solid during sampling.